Our hypothesis is that molecular variants at some loci affecting blood pressure regulation predispose individuals to the development of essential hypertension. Multifactorial determination and heterogeneity suggest that several genes may account for a predominant fraction of this genetic component. In this H-SCOR, we will be examining selected genes in patients with salt/volume sensitive hypertension as outlined in Projects 1 and 2. Analysis of genetic linkage, direct search for mutations, and genotyping at select loci may help in identifying 'genetic' subgroups for physiological studies in these two projects. This core will also assist investigators in projects 3-5 in marker development or other molecular genetic approaches as the need arise.